How to decide when a scroll rect will scroll down, or up

Hello!

I tried to find the answer or at least a pointer to this one for the past 2 days and it seems like what I'm trying to do might be impossible or something...

What I'm trying to do is to sort of recreate the SNES era final fantasy menus, meaning that you have about 10 rows of 2-3 elements on the screen at a time but you could have 50 more rows off screen.

I've seen tutorials on how to move the scroll rect with the keyboard (It seems a bit complex but I got time to learn) but the problem is that the items menu will move even if I'm not even close to the off screen rows...

I'm using a multi-dimensional array for the x and y coordinates in the rows * columns grid so ideally, the scroll rect will only move one 'row' down when I reach the 11th row (which is off screen, assuming there are only 10 rows visible). The question is though... How could I do that, if possible at all?